1. Field of the Invention
The present invention relates to an image forming apparatus such as a printer, a copier, a fax, and a scanner and particularly relates to an image forming apparatus including a process cartridge on which a recording medium is mounted.
2. Description of the Related Art
Typical image forming apparatuses, specifically, small so-called low-end apparatuses have employed a process cartridge system in which electrophotographic process units are detachable to the main bodies of the image forming apparatuses (Japanese Patent Application Laid-open No. 2009-109854 and Japanese Patent Application Laid-open No. 2008-185971). With this structure, the process units are formed into cartridges by integrating at least one of charging units, developing units, and cleaning units and photosensitive bodies as image carriers (these are members for electrostatic latent image forming process mechanism). When the photosensitive bodies or the developers are consumed, users themselves can perform action such as replacement of the photosensitive bodies and supply of the developers without depending on professional servicemen by employing the process cartridge system, which significantly improves the operability.
However, the service life of such process cartridges is determined by the frequency in use or the like, and thus, the states of the process cartridges such as the frequency in use need to be grasped and controlled. Therefore, a nonvolatile memory (read-only memory (ROM)) is mounted as a recording medium on a process cartridge disclosed in Japanese Patent Application Laid-open No. 2008-185971 or the like. The nonvolatile memory stores therein the amount used in the main body of the image forming apparatus. The application limit of the process cartridge is judged according to the information, and the replacement timing is informed to users. With such functions and objects, the main body of the image forming apparatus accesses the nonvolatile memory of the process cartridge at timing before and after image formation or after replacement of the process cartridge or similar timing.
As illustrated in FIG. 9, with this structure, an apparatus casing 100 of the main body of the apparatus includes a contact terminal 102, and a process cartridge 103 includes a recording medium 101 including a nonvolatile memory. The recording medium 101 generally slightly protrudes from a side surface 103a of the process cartridge 103.
As illustrated in FIG. 10, when the process cartridge 103 is mounted on the main body of the apparatus, the process cartridge 103 is inserted into the apparatus casing 100 along an arrow A direction. In other words, the process cartridge 103 is inserted along the arrow A direction while the side surface 103a of the process cartridge 103 in which the recording medium 101 is installed and an internal surface 100a of the apparatus casing 100 in which the contact terminal 102 is installed are maintained in a parallel state.
Some conventional inkjet printers include a circuit board that includes a storage unit recording information and a contact terminal connecting an external circuit with the storage unit and that is included in the main body of a container (Japanese Patent Application Laid-open No. 2007-237657). With this structure, the circuit board is maintained in an elastically displaceable manner that the contact terminal has a specified pressing load on a contact terminal provided at a container mounting part side.
As illustrated in FIG. 9 or similar figures, when the process cartridge 103 is inserted, the contact terminal 102 slides on the resist of the recording medium 101. However, abrasion powder may be generated by such sliding and may adhere to the contact terminal 102. The abrasion powder adhering to the contact terminal 102 may cause contact failure between the contact terminal 102 and the recording medium 101, failure of the contact terminal 102 due to the contact, and similar failure.
Moreover, even when the circuit board is maintained in an elastically displaceable manner as with the inkjet printer disclosed in Japanese Patent Application Laid-open No. 2007-237657, the contact terminal is supposed to be in sliding contact with (slide on) the contact terminal of the circuit board during the placement. Therefore, although the abrasion decreases to an extent, it will still occur. Accordingly, this structure has the same disadvantages as those illustrated in FIG. 9 or similar figures.
With the image forming apparatus of the present invention, when the process cartridge is inserted into the main body of the apparatus, the protruding portion of the contact terminal is in sliding contact with the slide contact surface portion of the process cartridge. During the sliding, the protruding portion is pressed in a direction of being apart from the recording medium to limit contact between the contact terminal and the recording medium. When the process cartridge reaches its predetermined mounted position, the protruding portion fits in a fitting concave portion, and the contact restriction of the contact terminal with the recording medium is released. Accordingly, the contact terminal comes in contact with the recording medium. On the other hand, when the process cartridge is in action of being taken out from the main body of the apparatus, the protruding portion of the contact terminal is in sliding contact with the slide contact surface portion of the process cartridge. During the sliding, the protruding portion is pressed in a direction of being apart from the recording medium to limit contact between the contact terminal and the recording medium.
Accordingly, in the image forming apparatus, the contact terminal comes in contact with the recording medium only when the protruding portion is in a state of fitting in the fitting concave portion. While the contact terminal comes in contact with the recording medium, no sliding occurs. Moreover, both the contact terminal side and the recording medium side are not abraded during the action of inserting and taking out the process cartridge.
Thus, the structure can be simplified by constituting the contact terminal with the plate spring member.
The cam member is replaceable when the protruding portion is formed of the cam member different from the member for the main body portion.
Thus, when the contact terminal includes the elastic member, the contact portion of the contact terminal can be pressed to the recording medium side, which enables the contact pressure between the contact portion of the contact terminal and the recording medium to be stabilized.
The contact reliability between the contact terminal and the recording medium can be improved by including the contact portion in plurality.
With such a structure, the protruding portion (cam member) can share the contact portion in plurality.